Immunoglobulin G4 (IgG4)-related disease is a chronic inflammatory condition often characterized by exudative pleural effusions. However, transudative pleural effusions, like in the presented case of an 80-year-old man with multiple comorbidities, are less common but possible. Despite initial treatment with diuretics, the effusion persisted, prompting further investigation. Medical thoracoscopy revealed lymphatic follicle hyperplasia and an abundance of IgG4-positive plasmacytoid cells, confirming IgG4-related pleuritis. This case underscores the importance of considering inflammatory etiologies, such as IgG4-related disease, when faced with unresponsive transudative pleural effusions. Thoracoscopy serves as a valuable diagnostic tool in such scenarios, allowing for precise diagnosis and appropriate management.

We should consider IgG4-related disease (IGRD) as one of the potential causes of constrictive pericarditis. In patients with constrictive pericarditis due to IGRD, the combination of surgical treatment and immunosuppressive therapy may be an effective strategy.

UNASSIGNED: This case highlights the importance of a definite diagnosis of an IgG4-related chronic sclerosing duodenitis based on histological and radiological findings to rule out any malignancy in the mass. While dealing with patients having concentric duodenal thickening resulting in stricture formation, one should think of inflammatory etiology as well. IgG4-related disease is one of these inflammatory disorders where we see soft tissue thickening without a large mass or any associated lymphadenopathy as in our case.
UNASSIGNED: Immunoglobulin G4-related disease (IgG4-RD) is distinguished as an infiltration of IgG-4-positive plasmacytes involving inflammatory lesions across multiple organs which is accompanied by raised IgG4 levels in the serum. Several inflammatory disorders are recognized as part of the IgG4-RD family based on shared histopathological features, which include Mikulicz\'s disease, chronic sclerosing sialadenitis, or Riedel\'s thyroiditis. Our case highlights a distinctive presentation of IgG4-related diseases; a 58-year-old man presenting with duodenal stricture highly suspicious of a duodenal mass/ampullary mass later found to be due to IgG4-related sclerosing duodenitis with negative malignancy on biopsy. We present the diagnostic challenges faced and relevant findings noted.

UNASSIGNED: IgG4-related disease is a rare and emerging pathology, characterized by the appearance of pseudotumors. Due to the ability to mimic other pathologies, it is essential to consider it as a differential diagnosis in multisystemic processes. The diagnosis is challenging, requiring a multidisciplinary approach, to minimize the associated morbidity and mortality.
UNASSIGNED: IgG4-related disease (IgG4-RD) is a rare, emerging, systemic and chronic pathology, characterized by the appearance of pseudotumors resulting from tissue infiltration by IgG4-positive plasma cells that promote eosinophilic inflammation of the tissue with subsequent fibrosis. We present the case of a male, 45-year-old patient, with marked weight loss and skin pallor detected by his family doctor during a child health consultation of his daughter. When questioned, the patient referred complaints of postprandial discomfort in the left hypochondrium with a feeling of fullness, weight loss, chronic fatigue and hyperhidrosis that had lasted for a month. On physical examination, he was pale, and had pain at palpation of the left hypochondrium. Laboratory data showed increased inflammation markers, abdominal ultrasound and CT demonstrated numerous enlarged lymph nodes in the upper quadrants, raising concern for a malignant lymphoproliferative process. Serological, imaging, clinical and laparoscopic excisional biopsy revealed features of IgG4-related disease and excluded malignant lymphoproliferative disease. The immediate response to treatment with oral prednisolone 30 mg/day also contributed for diagnosis confirmation. Due to refractory disease after gradual prednisolone reduction, second-line therapy with rituximab was initiated. Over the 6 years of follow-up, the patient presented multiple exacerbations characterized by the emergence of systemic symptoms, being maintained under close clinical and imaging follow-up by reumathology, infectious diseases, and family medicine specialists.

BACKGROUND: Chronic pancreatitis (CP) is common in English cocker spaniels (ECS). It is histologically similar to IgG4-related disease (IgG4-RD) in humans and is characterized by duct destruction, interlobular fibrosis, and dense periductular and perivenous lymphocytic aggregates. However, the clinical manifestations of CP in ECS have not been previously described.
OBJECTIVE: Characterize the clinical manifestations of CP in a group of ECS, including similarities and differences to IgG4-RD in humans.
METHODS: One-hundred four ECS with CP and 44 client owned control ECS without CP (both healthy and diseased controls).
METHODS: Affected dogs were divided into 2 groups according to the methods used to diagnose CP. Case records were searched for signalment, clinical, and clinicopathological findings, and evidence of keratoconjunctivitis sicca (KCS), proteinuria, other immune-mediated diseases, and anal sacculitis.
RESULTS: Involvement of other organs was common. Affected ECS presented with a high frequency of KCS (n = 49), proteinuria (n = 47), anal gland disease (n = 36), atopy (n = 21), and other immune-mediated diseases (n = 16). Those with parti-color hair coats, particularly blue roan, had a strong association with CP, suggesting a link between coat color and autoimmune conditions in this breed.
CONCLUSIONS: English cocker spaniels with CP show clinical similarities to humans with IgG4-RD and common involvement of other organs. Clinicians should evaluate affected Cocker Spaniels for proteinuria, keratoconjunctivitis sicca, and other potential immune-mediated diseases.

This study aimed to review the lesser-known intraoral manifestations of immunoglobulin G4-related disease (IgG4-RD). In this paper we report an unprecedented case of oral IgG4-RD mimicking angiolymphoid hyperplasia with eosinophilia (ALHE), and another case presenting as plasma cell gingivitis. We then performed a scoping review of published cases of IgG4-RD involving the oral cavity. The following data were collected for each case: age, sex, intraoral site(s) involved, clinical appearance, imaging features, serum IgG4 values, histopathology, treatment, and follow-up duration. Fifty-one cases of oral IgG4-RD were published in literature. The hard palate and jaw bones were the two main locations reported, while the histological identification of a IgG4/IgG plasma cells ratio ≥40% was fundamental for diagnosis. Conversely, the pathological features of storiform fibrosis and obliterative phlebitis were not common. Future reports regarding oral IgG4-RD should report clear adherence to the recognized international diagnostic criteria of the disease.

UNASSIGNED: Autoimmune pancreatitis (AIP) is a form of chronic pancreatitis scarcely found in children. Raghib syndrome is a rare congenital heart defect known as persistent left superior vena cava (LSVC) draining into the left atrium. Total signs of Raghib syndrome in AIP case accompanied by an IgG4-related disease were described.
UNASSIGNED: Autoimmune pancreatitis (AIP) is a form of chronic pancreatitis scarcely found in children. Raghib syndrome is a rare congenital heart defect known as persistent left superior vena cava (LSVC) draining into the left atrium. Here, we describe Raghib syndrome in AIP case accompanied by an IgG4-related disease (AIP/IgG4RD). A 13-year-old boy presented with a 3-month history of fever and abdominal pain. The laboratory findings showed SGOT and SGPT, ALP was increased, while amylase and γ-GT were normal. Immunoglobulins were normal, except for IgG. Endosonography, spiral CT of the abdomen, and cholangiopancreatography showed an enlargement of the pancreas. Contrast echocardiography discovered opacification of the coronary sinus and left atrium. Transesophageal echocardiography for LSVC revealed a dilatation in the coronary sinus, indicating persistent LSVC. Following the injection of agitated saline into the left antecubital vein, bubbles entered both left and right atria in LSVC. It is reasonable to exclude some of these rare disorders as Raghib syndrome, in cases that will be started on medications like corticosteroids, which increases the susceptibility to thromboembolic events.

Immunoglobulin G4 (IgG4)-related disease is a chronic fibroinflammatory disease mediated by immune disorders. Given the challenging clinical diagnosis and treatment, knowledge of the pathogenesis of IgG4-related disease is important. The typical elevation of serum IgG4 concentrations and infiltration of IgG4-positive plasma cells in the involved tissues indicate the involvement of B lymphocytes in the pathogenesis of IgG4-related disease. Mass production of autoantibodies reflects abnormal activation of B cells, which causes tissue damage. Circulating plasmablasts are recently discovered markers that correlate with serum IgG4 concentration, the extent of organ involvement and disease activity. B-cell depletion therapy is an emerging curative strategy that can significantly alleviate clinical manifestations and achieve remission in patients with IgG4-related disease. These findings highlight the potential role of B cells in IgG4-related disease. In this review, we discuss the pathogenic impact of B lymphocytes on IgG4-related disease and describe novel therapies targeting B cells.

Immunoglobulin G4-related disease (IgG4-RD) is a newly recognized disease, and therefore its clinical features are not yet fully understood. Here, we describe a surgical case of metachronous bilateral IgG4-related pleuritis and postoperative chylothorax. This case could provide key insights into the pathology of IgG4-RD from a surgical perspective. We present a 70-year-old woman who had a right pleural mass. Video-assisted thoracoscopic pleural mass resection was performed, and the patient was diagnosed with right-sided IgG4-related pleuritis. Two years later, she was also diagnosed with left-sided IgG4-related pleuritis. We suspected the presence of IgG4-positive plasma cell infiltration. Additionally, she experienced a complicated postoperative chylothorax on the left side. It is important to consider the altered course of lymphatic vessels when extensively removing the pleura near the right thoracic duct. The occurrence of metachronous bilateral IgG4-associated pleuritis has not been previously reported, making this case particularly significant for understanding the pathology of IgG4-RD from a surgical standpoint.

UNASSIGNED: To describe the rare presentation, imaging and histological findings, and treatments in patients with IgG4-related disease (IgG4-RD) and diagnostic pitfalls and difficulties.
UNASSIGNED: Cases of sinonasal IgG4-RD were retrieved, and clinicopathological features were reviewed.
UNASSIGNED: Seven cases of sinonasal IgG4-RD were identified over an 11-year period, including four males and three females, with an age range of 19-66 years (median 58 years). Patients presented with symptoms related to the mass effect of the lesions or the destructive nature of the disease including fullness, swelling, obstruction, and pain. Serum IgG and IgG4 levels, IgG/IgG4 ratios, storiform fibrosis, obliterative phlebitis, and plasma cell infiltration were seen in varying proportions. Bony erosion and tissue inflammation were present in some cases.
UNASSIGNED: Sinonasal IgG4-RD is exceedingly rare among other IgG4-RD and varied in its clinical presentation thus posing as a clinically difficult disease to diagnosis. Proper clinical, pathological, and immunohistopathological analysis is required for accurate diagnosis. Such disease should be considered in all cases of similar presentation to those in this study.Level of Evidence: 4.